The purpose of this prospective study is to evaluate the efficacy of the ResAppDx software application in diagnosis of pneumonia and other respiratory conditions (bronchiolitis, asthma/reactive airway disease, croup, upper or lower respiratory tract infections) in infants and children. Patient's cough sounds will be recorded using a smartphone and analysed using the ResAppDx software. The ResAppDx diagnosis will be compared to radiologic diagnosis and/or clinical diagnosis. The ResAppDx diagnosis will not be provided to the clinician or patient.